Thirty-five people were ushered out of the center at 1550 North Garey Ave. as well as a nearby gas station and MRI center, said Pomona Police Cpl. Daryll Johnson.
Pomona police received the call about 8:44 a.m.
At the scene, a bomb-sniffing canine searched the building with help from six police officers. An ambulance service was on standby. The scene was cleared after two hours.
An operator at Planned Parenthood's Los Angeles administrative headquarters received a call from an unidentified person about a bomb at the Pomona center.
"That phone call was given to their head of security, who then called us," Johnson said.